Further Information

Hattersley PICV FAQ

01. Q. Can I measure flow rate?

A. No. Flow rate cannot be measured directly from the PICV. Other means of flow verification such as orifice plates/ flow measurement devices should be installed as part of the system. However, the flow rate can be established from valve set position.

02. Q. What are the test points used for?

A. They are used to verify the pressure drop across the seat to check that the valve is operating at the correct pressure drop. Please refer to the IOM.

03. Q. How do I know if the PICV is working correctly?

A. This can be verified by measuring the pressure drop across the seat using the test points and then comparing against the detail provided in FAQ 2.

04. Q. Can I install the PICV upside down?

A. The PICV can be mounted in any orientation. However consideration needs to be given to choice of actuator. Thermal actuators can be installed in any orientation, but Electro-Mechanical actuators should not be installed upside down as this can allow moisture to enter the actuator. However, a PICV with an electro-mechanical actuator can be orientated anywhere between 0-90° from the vertical.

05. Q. Can I install the PICV on flow or return?

A. The PICV can be installed on either flow and return. Please ensure that the valve is installed with the flow direction arrow in the correct direction.

06. Q. Does it matter which way around the PICV is installed?

A. The PICV must be installed with the flow direction arrow in the correct direction.

07. Q. How accurate is the pre-setting?

A. With careful alignment of the setting dial to desired flow rate position, a pre-set accuracy of +/- 10% can be achieved.

08. Q. Can I flush through the PICV?

A. It is not recommended to flush through PICVs. The PICV is a control valve with close tolerance flow paths. Flushing through these valves may introduce debris which could block the flow paths.

09. Q. Are the valves able to isolate?

A. Control valves are not designed to be isolating valves, and it is always recommended to fit separate isolating valves. However for routine maintenance purposes, i.e. strainer cleaning, the actuator can be removed, and a manual cap fitted which can be used to close the valve.

10. Q. How do I commission using PICVs?

A. BSRIA Guide to Commissioning Water Systems BG2 / 2010 and CIBSE Commissioning Code W: 2010 give details of commissioning procedures using PICVs.